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A review of low-temperature plasma-assisted machining: from mechanism to application

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0734-y

摘要： Materials with high hardness, strength or plasticity have been widely used in the fields of aviation, aerospace, and military, among others. However, the poor machinability of these materials leads to large cutting forces, high cutting temperatures, serious tool wear, and chip adhesion, which affect machining quality. Low-temperature plasma contains a variety of active particles and can effectively adjust material properties, including hardness, strength, ductility, and wettability, significantly improving material machinability. In this paper, we first discuss the mechanisms and applications of low-temperature plasma-assisted machining. After introducing the characteristics, classifications, and action mechanisms of the low-temperature plasma, we describe the effects of the low-temperature plasma on different machining processes of various difficult-to-cut materials. The low-temperature plasma can be classified as hot plasma and cold plasma according to the different equilibrium states. Hot plasma improves material machinability via the thermal softening effect induced by the high temperature, whereas the main mechanisms of the cold plasma can be summarized as chemical reactions to reduce material hardness, the hydrophilization effect to improve surface wettability, and the Rehbinder effect to promote fracture. In addition, hybrid machining methods combining the merits of the low-temperature plasma and other energy fields like ultrasonic vibration, liquid nitrogen, and minimum quantity lubrication are also described and analyzed. Finally, the promising development trends of low-temperature plasma-assisted machining are presented, which include more precise control of the heat-affected zone in hot plasma-assisted machining, cold plasma-assisted polishing of metal materials, and further investigations on the reaction mechanisms between the cold plasma and other materials.

关键词： low-temperature plasma     difficult-to-cut material     machinability     hydrophilization effect     Rehbinder effect    

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MHD effect on the critical temperature differences of oscillatory thermocapillary convection in two-layer

Hulin HUANG, Xiaoming ZHOU,

《能源前沿（英文）》 2010年 第4卷 第2期   页码 155-160 doi: 10.1007/s11708-009-0063-4

摘要： The effect of different directional magnetic fields on critical temperature differences of oscillatory thermocapillary convection in a rectangular cavity with differentially heated side walls filled with two viscous, immiscible, incompressible fluids is simulated in the absence of gravity. In this two-layer fluid system, the upper layer fluid is the electrically non-conducting encapsulant boron oxide (BO), while the lower one is the electrically conducting molten indium phosphide (InP). The interface between the two fluids is assumed to be flat and non-deformable. The computational results show that all the magnetic fields along the , and directions can delay the transition from steady convection to oscillatory convection, and critical temperature differences increase with an increasing Hartmann number. Furthermore, the effect of a magnetic field along the direction is strongest, followed by that along the direction, and that along the direction is the weakest for the same intensity of the magnetic field.

关键词： magnetohydrodynamic     magnetic fields     thermocapillary convection     critical temperature difference     oscillatory convection     two-layer fluid system    

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Evaluating the short-term effect of ambient temperature on non-fatal outdoor falls and road traffic injuries

《环境科学与工程前沿（英文）》 2023年 第17卷 第9期 doi: 10.1007/s11783-023-1705-1

摘要：

● A study assessing the temperature-injury relationship was conducted among students.

关键词： Ambient temperature     Fall     Road traffic injury     Student     China    

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Effect of extrusion temperature on the physical properties of high-silicon aluminum alloy

YANG Fuliang, GAN Weiping, CHEN Zhaoke

《机械工程前沿（英文）》 2007年 第2卷 第1期   页码 120-124 doi: 10.1007/s11465-007-0021-y

摘要： Light-weight high-silicon aluminum alloys are used for electronic packaging in the aviation and space-flight industry. Al-30Si and Al-40Si are fabricated with air-atomization and vacuum-canning hot-extrusion process. The density, thermal conductivity, hermeticity and thermal expansion coefficients of the material are measured, and the relationship between extrusion temperature and properties is obtained. Experimental results show that the density of high-silicon aluminum alloys prepared with this method is as high as 99.64% of the theory density, and increases with elevating extrusion temperature. At the same time, thermal conductivity varies between 104-140 W/(m " K); with the extrusion temperature, thermal expansion coefficient also increases but within 13?10 (at 100?C) and hermeticity of the material is high to 10 order of magnitude.

关键词： coefficient     hermeticity     temperature     relationship     air-atomization    

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Aspects of rock permeability

Lianyang ZHANG

《结构与土木工程前沿（英文）》 2013年 第7卷 第2期   页码 102-116 doi: 10.1007/s11709-013-0201-2

摘要： Effective evaluation of rock permeability is required in different energy, engineering and environmental projects. Although much research has been conducted on rock permeability, it is still one of the most difficult tasks for practicing rock engineers to accurately determine rock permeability. Based on a comprehensive literature review, this paper outlines the key aspects of rock permeability by presenting the representative values of the permeability of different rocks, describing the empirical and semi-empirical correlations for estimating the permeability of rocks, and discussing the main factors affecting the permeability of rocks. The factors discussed include stress, depth, temperature, and discontinuity intensity and aperture. This paper also highlights the scale effect on rock permeability, interconnectivity of discontinuities, and anisotropy of rock permeability. This paper provides the fundamental and essential information required for effective evaluation of rock permeability.

关键词： rock     permeability     discontinuity     stress     temperature     scale effect     anisotropy    

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Short-term effect of temperature variation on the competition between PAOs and GAOs during acclimation

Nanqi REN, Han KANG, Xiuheng WANG, Nan LI

《环境科学与工程前沿（英文）》 2011年 第5卷 第2期   页码 277-282 doi: 10.1007/s11783-010-0226-x

摘要： Sequencing batch reactor (SBR) for enhanced biological phosphorus removal (EBPR) processes was used to investigate the impact of the temperature shock on the competition between phosphorus-accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs) in start-up stage. During the 34 days operation, SBR was set with temperature variation(0–5 d, 22±1°C; 6–13 d, 29±1°C; 14–34 d, 14±1°C). PAOs and GAOs were analyzed by fluorescent in situ hybridization (FISH), and intracellular polyphosphate granules were stained by Neisser-stain. The results showed that the influence of temperature shock on PAOs’ abundance was more serious than that on GAOs in the enriching process. Under sudden and substantially temperature variation, from 22±1°C to 29±1°C and then to 14±1°C, the domination of PAOs was deteriorated. After temperature shock, PAOs’ competitive advantages at low temperature that concluded in other study did not appear in our study. As mesophilic, GAOs (indicated by and ) were more temperature adaptive and better grew and took the domination at 14±1°C in the end. In the competition process, organisms of tetrad forming organisms (TFOs)-like shape which were considered as typical GAOs, were observed. With the evidence of poly-P granules containing by Neisser-straining and result of FISH, these organisms of TFOs-like shape were better to be assumed as adaption state or a special self-protecting shape of PAOs.

关键词： fluorescent in situ hybridization (FISH)     tetrad forming organisms (TFOs)     temperature variation     enhanced biological phosphorus removal (EBPR)    

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investigation of evolutive mode-I and mode-II fracture behavior of fiber-reinforced cemented paste backfill: Effectof curing temperature and curing time

《结构与土木工程前沿（英文）》 2023年 第17卷 第2期   页码 256-270 doi: 10.1007/s11709-022-0924-z

摘要： The curing temperature-dependent cement hydration causes the nonlinear evolution of fracture behavior and properties of fiber-reinforced cemented paste backfill (CPB) and thus influences the stability of mine backfill materials in deep mines. Therefore, the coupled effect of curing temperature (20, 35, and 45 °C) and cement hydration at different curing times (3, 7, and 28 d) on the mode-I and mode-II fracture behavior and properties of fiber-reinforced CPB is investigated. A comprehensive experimental testing program consisting of semicircular bend tests, direct shear tests, measurement of volumetric water content and matric suction, TG/DTG tests, and SEM observation is carried out. The results show that the coupled thermochemical effect results in strongly nonlinear development of pre- and post-peak behavior of fiber-reinforced CPB. Moreover, the results discover a positive linear correlation between fracture toughness and shear strength parameters and also reveal the vital role played by matric suction in the formation of fracture toughness. Furthermore, predictive functions are developed to estimate the coupled thermochemical effect on the development of KIc and KIIc. Therefore, the findings and the developed mathematical tools have the potential to promote the successful application of fiber-reinforced CPB technology in deep underground mines.

关键词： fiber reinforcement     cemented paste backfill     fracture behavior     underground mine     cement hydration    

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Effect of distributions of fuel concentration and temperature on ignition processes in a diesel PCCI

Yang YU, Wanhua SU,

《能源前沿（英文）》 2010年 第4卷 第2期   页码 269-279 doi: 10.1007/s11708-009-0046-5

摘要： The distributions of fuel concentration and temperature have significant effect on the ignition processes of diesel premixed charge compression ignition (PCCI) combustion. It was found in this study that the ignition process of PCCI combustion organized by multi-pulse injection was strongly influenced by conditions of fuel stratification. The start of low temperature reactions occurred in the leaner area of the combustion chamber in the test engine because the temperature here first reached the point of low temperature reactions. Ignition always occurred in the position where the mixture featured with equivalence ratios close to the mean equivalence ratio of the overall mixture, while the neighboring area of the initial ignition area accumulate heat with a finite speed until finally autoigniting. Moreover, the appearance of highest combustion temperature occurred in the same area at the combustion chamber. For more homogeneous mixture, a higher amount of mixture reached ignition simultaneously, resulting in a larger initial ignition area and a higher temperature at the ignition area. Furthermore, V-type distribution of equivalence ratio was found to be beneficial to retarding high temperature reaction.

关键词： PCCI     fuel stratification     multi-pulse injection     ignition    

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Promotional effect of ion-exchanged K on the low-temperature hydrothermal stability of Cu/SAPO-34 and

Chen Wang, Jun Wang, Jianqiang Wang, Meiqing Shen

《环境科学与工程前沿（英文）》 2021年 第15卷 第2期 doi: 10.1007/s11783-020-1322-1

摘要： Abstract • K+ hinder the structural degradation of Cu/SAPO-34 under humid condition<100°C. • K+ on Cu/SAPO-34 brings lower acidity and inferior SCR activity at high temperature. • Fe/Beta was used to compensate the low activity of Cu/SAPO-34 at high temperature. • The hybrid catalysts with KCu/SAPO-34 and Fe/Beta show a great potential for using. K ions were introduced onto Cu/SAPO-34 catalysts via the ion-exchange process in order to improve their stability under low-temperature hydrothermal aging. The changes in structure and copper-species contents of these catalysts upon hydrothermal aging were probed in order to investigate their effects on selective catalytic reduction (SCR) activity. For the fresh Cu/SAPO-34 catalysts, K ions had little influence on the chabazite framework but effected their acidities by exchanging with acid sites. After hydrothermal aging, the structural integrity and amount of active sites decreased on pure Cu/SAPO-34. While the K-loaded catalysts showed improved chabazite structure, acidity, and active site conservation with increasing K loading. However, although the 0.7 wt% K catalyst maintained the same crystallinity, active site abundance, and low-temperature SCR activity as the fresh catalyst upon aging, an apparent decrease in SCR activity at high temperature was observed because of the inevitable decrease in the number of Brönsted acid sites. To compensate for the activity disadvantage of K-loaded Cu/SAPO-34 at high temperature, Fe/Beta catalysts were co-employed with K-loaded Cu/SAPO-34, and a wide active temperature window of SCR activity was obtained. Thus, our study reveals that a combined system comprising Fe/Beta and K-loaded Cu/SAPO-34 catalysts shows promise for the elimination of NOx in real-world applications.

关键词： Selective catalytic reduction     Cu/SAPO-34 catalyst     Ion-exchanged K     Low-temperature hydrothermal stability     Fe/Beta catalyst    

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Thermal analysis of lubricated three-dimensional contact bodies considering interface roughness

《机械工程前沿（英文）》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0672-8

摘要： Surface roughness and thermal action are of remarkable importance in the lubrication performance of mechanical components, especially in extreme conditions. However, available studies mainly focus on the full-film lubrication conditions without considering temperature rise and real 3D surface roughness due to the complexity of surface topography and temperature characteristics. Moreover, studies on the interfacial thermal behaviors of 3D rough surface lubricated contact in an extended range of working conditions remain limited. In this paper, a deterministic mixed thermal elastohydrodynamic lubrication model considering real 3D surface roughness and thermal effects is proposed. In this model, pressure and temperature are coupled with each other, the computation of elastic deformation is accelerated through the discrete convolution and fast Fourier transform method, the temperature field is calculated with the column sweeping technique, and the semi-system method is introduced to improve convergence and numerical stability under severe conditions. The model is validated by comparing its results with available published numerical and experimental results. The thermal behaviors of the contact interface are studied in a wide range of working conditions. The influences of surface roughness and thermal effect on lubrication performance are revealed. The results show that the proposed model can be used as a powerful analysis tool for lubrication performance and temperature prediction in various heavy-load, high-speed lubricated components over a wide range of lubrication conditions.

关键词： thermal elastohydrodynamic lubrication     surface roughness effect     thermal effect     temperature characteristics     severe conditions    

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of polyacrylamide (PAM) and methane production by mesophilic and thermophilic anaerobic digestion: Effectof temperature and concentration

Mona Akbar, Muhammad Farooq Saleem Khan, Ling Qian, Hui Wang

《环境科学与工程前沿（英文）》 2020年 第14卷 第6期 doi: 10.1007/s11783-020-1277-2

摘要： Abstract • PAM degradation in thermophilic AD in comparison with mesophilic AD. • PAM degradation and its impact on thermophilic and mesophilic AD. • Enhanced methane yield in presence of PAM during thermophilic and mesophilic AD. • PAM degradation and microbial community analysis in thermophilic and mesophilic AD. Polyacrylamide (PAM) is generally employed in wastewater treatment processes such as sludge dewatering and therefore exists in the sludge. Furthermore, it degrades slowly and can deteriorate methane yield during anaerobic digestion (AD). The impact or fate of PAM in AD under thermophilic conditions is still unclear. This study mainly focuses on PAM degradation and enhanced methane production from PAM-added sludge during 15 days of thermophilic (55°C) AD compared to mesophilic (35°C) AD. Sludge and PAM dose from 10 to 50 g/kg TSS were used. The results showed that PAM degraded by 76% to 78% with acrylamide (AM) content of 0.2 to 3.3 mg/L in thermophilic AD. However, it degraded only 27% to 30% with AM content of 0.5 to 7.2 mg/L in mesophilic AD. The methane yield was almost 230 to 238.4 mL/g VSS on the 8th day in thermophilic AD but was 115.2 to 128.6 mL/g VSS in mesophilic AD. Mechanism investigation revealed that thermophilic AD with continuous stirring not only enhanced PAM degradation but also boosted the organics release from the sludge with added PAM and gave higher methane yield than mesophilic AD.

关键词： Polyacrylamide (PAM) degradation     Acrylamide (AM)     Mesophilic anaerobic digestion     Thermophilic anaerobic digestion     Methane production    

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Applicability of the Arrhenius model for Ammonia Oxidizing Bacteria subjected to temperature time gradients

Alberto MANNUCCI,Giulio MUNZ,Gualtiero MORI,Claudio LUBELLO,Jan A. OLESZKIEWICZ

《环境科学与工程前沿（英文）》 2015年 第9卷 第6期   页码 988-994 doi: 10.1007/s11783-014-0751-0

摘要： The aim of this work is to identify the range of applicability of Arrhenius type temperature dependence for Ammonia Oxidizing Bacteria (AOB) subjected to temperature time gradients through continuous titrimetric tests. An innovative online differential titrimetric technique was used to continuously monitor the maximum biologic ammonia oxidation rate of the biomass selected in a pilot scale membrane bioreactor, as a function of temperature time gradients. The monitoring technique is based on the measurement of alkalinity and hydrogen peroxide consumption rates in two parallel reactors operated in non-limiting substrate conditions for AOB; both reactors were continuously fed with mixed liquor and in one of them AOB were inhibited with allylthiourea. The effects of temperature decrease rates in the range 1 to 4°C·h were evaluated by controlling the titrimetric reactor in the temperature range 10°C–20°C. The dependence of growth kinetics on temperature time gradients and the range of applicability of Arrhenius model for temperature dependency of AOB growth kinetics were assessed. The Arrhenius model was found to be accurate only with temperature gradients lower than 2°C·h . The estimated Arrhenius coefficients ( ) were shown to increase from 1.07 to 1.6 when the temperature decrease rate reached 4°C·h .

关键词： nitrification rate     temperature effect     continuous titrimetric tests     time-gradient temperature variations     Ammonia Oxidizing Bacteria (AOB)    

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Temperature effects of shape memory alloys (SMAs) in damage control design of steel portal frames

Xiaoqun LUO, Hanbin GE, Tsutomu USAMI

《结构与土木工程前沿（英文）》 2012年 第6卷 第4期   页码 348-357 doi: 10.1007/s11709-012-0176-4

摘要： The objective of the present study is to analytically investigate temperature effects of an axial-type seismic damper made of shape memory alloys (SMAs) equipped in steel frames. Based on a modified multilinear one dimensional constitutive model of SMAs, two types of SMAs are employed, which have different stress plateau and different stress growth rate with temperature increase. Temperature effects of SMA dampers on seismic performance upgrading are discussed in three aspects: different environment temperatures; rapid loading rate induced heat generation and different SMA fractions. The analysis indicates that the effect of environment temperature should be considered for the SMA damper in steel frames. However, the rapid loading rate induced heat generation has little adverse effect.

关键词： damage control design     shape memory alloy     temperature effect    

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Effect of temperature in the conversion of methanol to olefins (MTO) using an extruded SAPO-34 catalyst

Ignacio Jorge Castellanos-Beltran, Gnouyaro Palla Assima, Jean-Michel Lavoie

《化学科学与工程前沿（英文）》 2018年 第12卷 第2期   页码 226-238 doi: 10.1007/s11705-018-1709-8

摘要： The methanol-to-olefin (MTO) reaction was investigated in a bench-scale, fixed-bed reactor using an extruded catalyst composed of a commercial SAPO-34 (65 weight percentage, wt-%) embedded in an amorphous SiO matrix (35 wt-%). The texture properties, acidity and crystal structure of the pure SAPO-34 and its extruded form (E-SAPO-34) were analyzed and results indicated that the extrusion step did not affect the properties of the catalyst. Subsequently, E-SAPO-34 was tested in a temperature range between 300 and 500 °C, using an aqueous methanol mixture (80 wt-% water content) fed at a weight hour space velocity (WHSV) of 1.21 h . At 300 °C, a low conversion was observed combined with catalyst deactivation, which was ascribed to oligomerization and condensation reactions. The coke analysis showed the presence of diamandoid hydrocarbons, which are known to be inactive molecules in the MTO process. At higher temperatures, a quasi-steady state was reached during a 6 h reaction where the optimal temperature was identified at 450 °C, which incidentally led to the lowest coke deposition combined with the highest H/C ratio. Above 450 °C, surges of ethylene and methane were associated to a combination of H-transfer and protolytic cracking reactions. Finally, the present work underscored the convenience of the extrusion technique for testing catalysts at simulated scale-up conditions.

关键词： MTO     SAPO-34     temperature     extrusion     coke     light alkanes    

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Effect of K and Ca on catalytic activity of Mn-CeO

Boxiong SHEN, Lidan DENG, Jianhong CHEN

《环境科学与工程前沿（英文）》 2013年 第7卷 第4期   页码 512-517 doi: 10.1007/s11783-013-0519-y

摘要： Mn-CeO /Ti-pillared clay (PILC) is an attractive catalyst for selective catalytic reduction of NO at low temperature because of its low cost. The poisoning of K and Ca on the catalyst of Mn-CeO /Ti-PILC is an important problem because K and Ca are always in presence in flue gas. To investigate the effect of K and Ca on the physicochemical characters of the catalysts, the techniques of NH -temperature programmed desorption (TPD), H -temperature programmed reduction (TPR), and X-ray photoelectron spectroscopy (XPS) were used to analyze the fresh and deactivated catalysts of Mn-CeO /Ti-PILC. (Ca)Mn-CeO /Ti-PILC and (K)Mn-CeO /Ti-PILC are denoted for the dopes of the catalyst of Mn-CeO /Ti-PILC with Ca and K, respectively. The activities of Mn-CeO /Ti-PILC, (Ca)Mn-CeO /Ti-PILC and (K)Mn-CeO /Ti-PILC for NH -selective catalytic reduction (SCR) reaction at low temperature were investigated. The results showed that with the dopes of K and Ca on the catalysts, the SCR activities of the catalysts decreased greatly, and K exhibited more poisoning effect than Ca. With the dopes of K and Ca, the acidity, the redox property and chemisorbed oxygen on the surfaces of the catalysts were decreased, which resulted in a decreasing in SCR activity.

关键词： Mn-CeOx/Ti-pillared clay (PILC)     low-temperature selective catalytic reduction (SCR)     K and Ca poisoning effect    

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标题 作者 时间 类型 操作

A review of low-temperature plasma-assisted machining: from mechanism to application

期刊论文

MHD effect on the critical temperature differences of oscillatory thermocapillary convection in two-layer

Hulin HUANG, Xiaoming ZHOU,

期刊论文

Evaluating the short-term effect of ambient temperature on non-fatal outdoor falls and road traffic injuries

期刊论文

Effect of extrusion temperature on the physical properties of high-silicon aluminum alloy

YANG Fuliang, GAN Weiping, CHEN Zhaoke

期刊论文

Aspects of rock permeability

Lianyang ZHANG

期刊论文

Short-term effect of temperature variation on the competition between PAOs and GAOs during acclimation

Nanqi REN, Han KANG, Xiuheng WANG, Nan LI

期刊论文

investigation of evolutive mode-I and mode-II fracture behavior of fiber-reinforced cemented paste backfill: Effectof curing temperature and curing time

期刊论文

Effect of distributions of fuel concentration and temperature on ignition processes in a diesel PCCI

Yang YU, Wanhua SU,

期刊论文

Promotional effect of ion-exchanged K on the low-temperature hydrothermal stability of Cu/SAPO-34 and

Chen Wang, Jun Wang, Jianqiang Wang, Meiqing Shen

期刊论文

Thermal analysis of lubricated three-dimensional contact bodies considering interface roughness

期刊论文

of polyacrylamide (PAM) and methane production by mesophilic and thermophilic anaerobic digestion: Effectof temperature and concentration

Mona Akbar, Muhammad Farooq Saleem Khan, Ling Qian, Hui Wang

期刊论文

Applicability of the Arrhenius model for Ammonia Oxidizing Bacteria subjected to temperature time gradients

Alberto MANNUCCI,Giulio MUNZ,Gualtiero MORI,Claudio LUBELLO,Jan A. OLESZKIEWICZ

期刊论文

Temperature effects of shape memory alloys (SMAs) in damage control design of steel portal frames

Xiaoqun LUO, Hanbin GE, Tsutomu USAMI

期刊论文

Effect of temperature in the conversion of methanol to olefins (MTO) using an extruded SAPO-34 catalyst

Ignacio Jorge Castellanos-Beltran, Gnouyaro Palla Assima, Jean-Michel Lavoie

期刊论文

Effect of K and Ca on catalytic activity of Mn-CeO

Boxiong SHEN, Lidan DENG, Jianhong CHEN

期刊论文